| Abstract: | A method is demonstrated to prepare graphene dispersions at high concentrations, up to 1.2 mg mL?1, with yields of up to 4 wt% monolayers. This process relies on low‐power sonication for long times, up to 460 h. Transmission electron microscopy shows the sonication to reduce the flake size, with flake dimensions scaling as t?1/2. However, the mean flake length remains above 1 µm for all sonication times studied. Raman spectroscopy shows defects are introduced by the sonication process. However, detailed analysis suggests that predominately edge, rather than basal‐plane, defects are introduced. These dispersions are used to prepare high‐quality free‐standing graphene films. The dispersions can be heavily diluted by water without sedimentation or aggregation. This method facilitates graphene processing for a range of applications. |
